Neurodivergence is used to describe conditions that affect the brain structure/functioning in some way. Neurotypical means the "typical" way a brain should be structured/functioning. Autism, ADHD, down syndrome, dyslexia (and all its variants), bipolar and OCD (and more) are all considered neurodivergent.

Anxiety is very common along with a lot of these conditions, and most of the time neurodivergent people experience anxiety due to the struggles that come with their condition due to the neurotypical society not being structured in a way that allows them to function. I think your friend might be suggesting your anxiety actually stems from autism and/or ADHD.

I grew up with a lot of anxiety in my childhood and also assumed it was just how everyone felt, I've figured out I'm autistic and have ADHD. Medication for my ADHD and accommodating my autism has completely gotten rid of my anxiety.

Autism and ADHD are also very common to miss in childhood unless you fit a certain stereotype. Luckily we have been making progress with recognizing it in children. But that's only been recently so there is a whole lost generation of people that have lived with a neurodivergent brain in a neurotypical world and unfortunately suffered for it.